<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*nihaowa*/
        div {
            margin: 0 auto;
            width: 200px;
            height: 100px;
            border: 2px darkgreen;
            background: aliceblue;
            text-align: center;
            line-height: 100px;
        }

        p{
            font-size: 100px;
        }

        a {
            text-decoration: none;
            color: darkgreen;
        }

        div:hover{
            font-size: xx-large;
        }
    </style>
</head>
<body>
<div>
    div+head+style
    <p>hahah</p>
    <a href="https://www.baidu.com">百度</a>
</div>

</body>
</html>